title: Interleukin-1β suppresses activity of an inwardly rectifying K+ channel in human renal proximal tubule cells.
abstract: We investigated the effect of interleukin-1β (IL-1β) on activity of an inwardly rectifying K+ channel in cultured human proximal tubule cells (RPTECs), using the patch-clamp technique and Fura-2 Ca2+ imaging. IL-1β (15 pg/ml) acutely reduced K+ channel activity in cell-attached patches. This effect was blocked by the IL-1 receptor antagonist (20 ng/ml), an inhibitor of phospholipase C, neomycin (300 μM), and an inhibitor of protein kinase C (PKC), GF109203X (500 nM). The Fura-2 Ca2+ imaging revealed that IL-1β increased intracellular Ca2+ concentration even after removal of extracellular Ca2+, which was blocked by an inhibitor of inositol 1,4,5-trisphosphate receptors, 2-aminoethoxydiphenyl borate (2-APB, 1 μM). Moreover, IL-1β suppressed channel activity in the presence of 2-APB without extracellular Ca2+. These results suggest that IL-1β suppresses K+ channel activity in RPTECs through binding to its specific receptor and activation of the PKC pathway even though intracellular Ca2+ does not increase.
authors.affiliation: Department of Physiology, Iwate Medical University School of Medicine, 2-1-1 Nishitokuta, Yahaba 028-3694, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Nakamura
authors.forename: You
authors.initials: Y
authors.lastname: Komagiri
authors.forename: Manabu
authors.initials: M
authors.lastname: Kubokawa
mesh_terms: D000328:Adult; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D016257:Fura-2 / Q000378:metabolism; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D001896:Boron Compounds; D053496:Inositol 1,4,5-Trisphosphate Receptors; D053583:Interleukin-1beta; D024661:Potassium Channels, Inwardly Rectifying; C109986:2-aminoethoxydiphenyl borate; D011493:Protein Kinase C; D002118:Calcium; D016257:Fura-2